c# - Logic behind updating object List using linq -

c# - Logic behind updating object List using linq -

i have list of poco objects, why next code:

elements.where(x => x.param1 == "m").select(x => x.param2= "").tolist();

(tl;dr; sets param2 = "" on every element param1 equals m)

updates enumerable while one:

elements.where(x => x.param1 == "m").select(x => x.param2= "");

does not update it?

notice i'm doing neither elements = elements.where... nor var results = elements.where...

your sec code snippet without tolist query. need iterate execute it. calling tolist executes original query , since in select modifying property of object, see effect (or side effect) in original list. related parameter passing in c#. since lambda look in select anonymous method receiving parameter object of list. later when modify 1 of it's property see effect.

similarly if seek set object null not see side effect.

.select(x => x = null).tolist();

c# linq